wobbly scorpa Posted January 5, 2015 Report Share Posted January 5, 2015 Hi guys ... My newest scorpa , the sy 250 F four banger ..is a ripper ,, but the "flat spot" off idle is driving me bonkers (huge thanks to Paul at the hell team in OZ for all your help and info ) and I guess that with such a forum of smart people here I should throw it out to the room .. What have you done to reduce the flat spot /hessitation just after idle on this bike ....? or do I just learn to live with it ...... or find a breaking late model wrf and steal the efi out of it ..... any ideas ?? (apart from selling it ) Quote Link to comment Share on other sites More sharing options...
breagh Posted January 5, 2015 Report Share Posted January 5, 2015 Has it got the later pump type carb fitted? Quote Link to comment Share on other sites More sharing options...
wobbly scorpa Posted January 5, 2015 Author Report Share Posted January 5, 2015 tis the 06 , non pumper carb ...so I guess that will be my next move (or a home made EFI using string and and old toaster) I am thinking of raising the idle speed a bit .... but looking at all options at this stage Quote Link to comment Share on other sites More sharing options...
breagh Posted January 5, 2015 Report Share Posted January 5, 2015 I've had one about 5 years with the later carb and TBH it took me about 2 years fiddling to get it "rightish". I always run the idle speed high like a 4rt,this helps a bit. As yours is the older carb I can't really help ,I've only come across owners of a couple of them,both didn't run right. One tip, to remove the carb which is a pain take the rubber hose of the front of the airbox. Best of luck. 1 Quote Link to comment Share on other sites More sharing options...
eddie_lejeune Posted January 5, 2015 Report Share Posted January 5, 2015 I remember reading a pdf with regards to setting it up, again I would ask Paul Arnott he knows his stuff ref these bikes Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 5, 2015 Report Share Posted January 5, 2015 This is an inherent problem with single cylinder 4 stroke engines, probably the reason Mont / Honda went EFI with the 4RT. The cheapest solution is to find a secondhand CV carb. One of a Kawasaki KLX 250 should work Ok with a few jettng changes. If you can't get one of those a CV carb off a multi cylinder road bike should do. try to get one where the carb serves a cylinder of between 200 and 250cc. Beta use Cv carbs on their 4T trials bikes so it may be worth trying one of those if you can borrow one. 1 Quote Link to comment Share on other sites More sharing options...
wobbly scorpa Posted January 6, 2015 Author Report Share Posted January 6, 2015 i have been dreaming of the EFI kits on the web .....will do some more research .....the rest of the bike is fantastic ....it's just that tiny delay as one opens the throttle ........ and seeing that I am so crap at trials I need all the help I can get .....or I just keep riding this and blame my shocking score on the throttle lag ...ha ha ha Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 6, 2015 Report Share Posted January 6, 2015 (edited) Try a few sites in Japan. They are the only ones that ride that thing! http://www.trial4fun.com/2014/11/25/2014-japan-trial-championship-final-round-tohoku-winner-kenichi-kuroyama/ Edited January 6, 2015 by lineaway 1 Quote Link to comment Share on other sites More sharing options...
wobbly scorpa Posted January 6, 2015 Author Report Share Posted January 6, 2015 Try a few sites in Japan. They are the only ones that ride that thing! http://www.trial4fun.com/2014/11/25/2014-japan-trial-championship-final-round-tohoku-winner-kenichi-kuroyama/ perhaps they don't this problem ...... I am a big Aussie ....like 5 japs strapped together weight (and skills) wise.. Thanks for the heads up ...... I know i should just buy a 2 banga ,..... but i am too pig headed to stop beating my head against the wall ....... just yet Quote Link to comment Share on other sites More sharing options...
breagh Posted January 6, 2015 Report Share Posted January 6, 2015 I would question if there's enough room to fit anything other than the standard. set ups. Frankly access is dire. The later carb is acceptable but I think there were more changes than that. Feeling the earlier ones not got a restricter in the inlet manifold. Happy fiddling.. Quote Link to comment Share on other sites More sharing options...
eddie_lejeune Posted January 6, 2015 Report Share Posted January 6, 2015 id say that bike of kuroyamas in the link above is a 350 lol. Quote Link to comment Share on other sites More sharing options...
wobbly scorpa Posted January 6, 2015 Author Report Share Posted January 6, 2015 i am thinking of one of these ... http://www.ecotrons.com/products/small_engine_fuel_injection_kit/ .. anybody had any experience , good or bad with diy efi ? Quote Link to comment Share on other sites More sharing options...
wobbly scorpa Posted January 6, 2015 Author Report Share Posted January 6, 2015 I would question if there's enough room to fit anything other than the standard. set ups. Frankly access is dire. The later carb is acceptable but I think there were more changes than that. Feeling the earlier ones not got a restricter in the inlet manifold. Happy fiddling.. cheers .. It appears that it has both a venturi splitter on the airbox side and a diffuser (a disc with 2 vertical vanes in it ) ..... I reckon they struggled on , tried everything ...then got sick of it ...then released it onto the marketplace.... I will up the idle ..... start with the basics first .... The rest of the bike and the power delivery is fantastic . it's just the initial stumble that gives me the dabs Quote Link to comment Share on other sites More sharing options...
htrdoug Posted January 6, 2015 Report Share Posted January 6, 2015 http://www.delphi.com/manufacturers/other/powertrain/small Don't know how you acquire the setup,can't be too dire,Zongshen is selling a 250cc adventure bike with this setup for 3500USD complete.Only caveat is efi likes to have 4 litres of fuel in the tank minimum to cool the fuel pump,I'm sure an enterprising soul could sort a solution. Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted January 7, 2015 Report Share Posted January 7, 2015 Might be worth a look on the Bradford Ignitions website where they say they have a carb kit which "eradicates all the problems associated with starting and running of the 4T"? Quote Link to comment Share on other sites More sharing options...
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